Many attempts have been made to develop treatments and formulations to extend the human lifespan. To date, few, if any of these attempts have produced superior results, as few approaches fully recognize the basis or causes of aging. It is important to know the causes of aging, because as with treating a disease, one must first understand the problem, so that a precise remedy can be applied.
Some of the current theories of aging may be a result of other older conventional theories. Many of these theories are interlinked, in the same complex way that biological processes of the body and the many factors affecting these processes are interlinked.
Approaching any one or a combination of the following theories with a specialized treatment protocol may address and treat the aging problem on different levels, and help to slow down and eradicate some of the causes of aging. In order to appreciate the diversity of thought on the causes of aging, some of the current theories of aging are outlined below.
The DNA and Genetic Theories
Some scientists regard the DNA and genetic theories as planned obsolescence theories because they focus on the encoded programming within DNA. DNA is the blueprint of individual life obtained from one's parents. Humans are born with a unique code and a predetermined tendency to certain types of physical and mental functioning that regulate the rate at which one ages.
This type of genetic clock can be greatly influenced with regard to its rate of timing. For example, DNA is easily oxidized and this damage can be accumulated from diet, lifestyle, toxins, pollution, radiation and other outside influences. Thus, each individual has the ability to accelerate DNA damage or slow it down.
One recent theory regarding gene damage is the telomerase theory of aging. A telomere is the repetitive DNA sequence located at the end of a chromosome which shortens progressively with each cell division and limits the replicative potential of normal human somatic cells. It is now understood that telomeres, the sequences of nucleic acids extending from the ends of chromosomes, shorten every time a cell divides. This shortening of telomeres is believed to lead to cellular damage due to the inability of the cell to duplicate itself correctly. Each time a cell divides it duplicates itself a little less accurately or worse than the time before. This eventually leads to cellular dysfunction, aging and death.
Further research indicates that telomeres can be repaired by the introduction of a relevant hormone. Telomeres and their subsequent processes affect each other. Once we know what each telomere is responsible for, we may precisely introduce the necessary hormone and aid genetic repair, as well as hormonal balance.
Another key element in rebuilding the disappearing telomeres is the enzyme telomerase, an enzyme so far only found in germ and cancer cells. Telomerase appears to repair and replace telomeres helping to re-regulate the clock that controls the lifespan of dividing cells.
The Neuroendocrine Theory
This theory of aging elaborates on wear and tear by focusing on the neuroendocrine system. This system is a complicated network of biochemicals that govern the release of hormones which are altered by the walnut sized gland, the hypothalamus, located in the brain.
The Free Radical Theory
The term free radical describes any molecule that has a free electron. This property makes the free radical molecule react with healthy molecules in a destructive way. Because the free radical molecule has an extra electron, it creates an extra negative charge. This unbalanced energy makes the free radical bind itself to another balanced molecule. In so doing, the balanced molecule becomes unbalanced and thus a free radical itself. It is known that diet, lifestyle, drugs (e.g. tobacco and alcohol) and radiation are all accelerators of free radical production within the body and can influence the rate of aging.
The Membrane Theory of Aging
According to this theory, it is the age-related changes of the cells' ability to transfer chemicals, heat and electrical processes that impair the integrity of the cells.
As one grows older the cell membrane becomes less lipid, less watery and more solid. This impedes its efficiency to conduct normal cell functions. In particular, this can lead to a toxic accumulation within the cell. This cellular toxin is referred to as lipofuscin and as one grows older lipofuscin deposits become more present in the brain, heart and lungs and also in the skin. Some of the skin age-pigments referred to as liver spots or age spots are composed of lipofuscin. It is known that Alzheimer disease patients have much higher levels of lipofuscin deposits than compared to their healthy control groups. The cells' declining efficiency also means that the essential and regular transfer of sodium and potassium is impaired, thus reducing cellular communication. It is also believed that electrical conduction and heat transfer is also impaired by this cellular degradation.
The Hayflick Limit Theory
The Hayflick Limit Theory of aging suggests that the human cell is limited in the number of times it can divide. Part of this theory may be affected by cell waste accumulation (which is described in the Membrane Theory of aging). It is theorized that the human cell's ability to divide is limited to approximately 50 times, after which it simply stops dividing (and hence dies). It has been shown that nutrition has an effect on cells, with overfed cells dividing much faster than underfed cells. As cells divide to help repair and regenerate themselves the DNA & Genetic Theory of Aging may play a role. Each time a cell divides it may lose some blue-print information. Eventually (after 50-odd times of division) there is simply not enough DNA information available to complete any sort of division.
The Mitochondrial Decline Theory
The mitochondria are the power producing organelles found in every cell of every organ. Their primary job is to create adenosine triphosphate (ATP). They do so in the various energy cycles that involve nutrients such as acetyl-L-carnitine, CoQ10 (idebenone), NADH and some B vitamins. As the mitochondria decline, aging increases.
The Cross-Linking Theory
The Cross-Linking Theory of aging is also referred to as the glycosylation theory of aging. In this theory, it is the binding of glucose (simple sugars) to protein, (a process that occurs under the presence of oxygen) that causes various aging problems. Once this binding has occurred, the protein becomes impaired and is unable to perform as efficiently. Living a longer life leads to the increased possibility of oxygen meeting glucose and binding glucose to protein. This can lead to cross-linking disorders including senile cataracts and the appearance of tough, leathery and yellow skin.